Device for controlling the operation of electric switches



Nov. 6, 1951 KING 2,574,397

DEVICE FOR CONTROLLING THE OPERATION OF ELECTRIC SWITCHES Filed D66. 5,1950 Patented Nov. 6, 1951 DEVICE FOR CONTRQLLINGTHE OPERA- TION FELECTRIC SWITCHES Donald Mayer King, Hitchin, England ApplicationDecember 5, 1950, Serial No. 199166 In Great Britain December 22, 1949This invention relates to electric switches of the kind which areadapted t be mounted in an elevated position and to be actuated throughthe medium of a rocker arm or the like which is in turn operated bymeans of cords or the like which depend therefrom.

It is the object of the invention t evolve a single handle or gripmember to which the two operating cords associated with a switch of thetype referred to may be attached, such handle being so constructed andarranged that either of said cords maybe operated as required by anyperson grasping said handle or grip member.

According to the invention the handle or grip member comprises a firstmember to which one operating cord may be attached, a second member towhich the second cord may be attached, said two members being capable ofsliding movement relatively to each other, resilient means adaptednormally to couple said members together and capable of returning themautomatically to predetermined relative positions after slidingmovement, and means operable at will to prevent relative slidingmovement of said members when required. Preferably the handle or gripmember comprises an outer casing to which one cord is attached, a memberdisposed within said casing and slidable axially relatively thereto andto which the second cord is attached, means operable to prevent slidingmovement of said member relatively to the casing when required and meansadapted to return the parts to their original positions on thoseoccasion when relative movement has taken place.

In order that the invention may be more clearly understood and readilycarried into effect the same will be hereinafter more fully describedwith reference to the accompanying drawing which shows a section takenlongitudinally through a handle or grip member.

Referring now to the drawing it will be seen that the handle or gripmember comprises-an outer casing IQ of cylindrical form which is adaptedto house a piston or plunger member II the latter being so dimensionedthat it is capable of an axial sliding movement within and relatively tosaid outer casing. Disposed Within the piston or plunger member II is acoil spring I2 which is anchored at one end to a cap I3 serving to closeone end of the casing II! and at the other to a pin I4 carried by saidmember I I. Mounted externally of the casing I0 is a resilient triggerelement I5 in the form of a leaf spring said trigger element having aprojecting portion or nose I'B which is adapted on depression of theelement to 5 Claims. (Cl. 74--501) be projected through a slot oraperture H in the wall of the casing Ill and to engage the head of thepistonor plunger member I I thereby to prevent axial movement of thelatter relative to the casing. In the drawing the trigger element I5 isshown in full lines in its normal or inoperative position and in dottedlines in the depressed or operative position.

The handle or grip member is adapted to be attached to two cords whichdepend from a rocker arm coupled to a switch the arrangement being suchfor example that when one cord is pulled downwardly the rocker arm willbe moved to effect closure of the switch, while when the other cord ispulled said arm will be restored to its initial position thereby movingthe switch to the on position. In certain circumstances the switch to becontrolled may be of the self-return type the arrangement being suchthat upon cessation of a downward pull on one or other of the cords,said switch will return automatically to its initial or off position.

In the drawing the cords above referred to are designated I8 and I9 andit will be seen that the cord I 8 is attached to the piston or plungermember II while the other cord I9 is attached to a bracket or projection20 formed on the casing ID.

The arrangement is such that with the switch (to the rocker arm of whichthe cords I8 and I9 are attached) in the off position the cord I9attached to the outer casing, will be slack while the cord I8 attachedto the piston or plunger II, will be fully extended and will support theweight of the handle or grip member. In this arrangement when it isrequired to operate the switch the trigger element I5 will be depressedto prevent axial movement of the casing I0 relatively to the piston orplunger member II and the handle or grip member as a whole will bepulled downwardly thereby to exert a pull on the cord I8 which serves tomove the rocker arm and thereby to actuate the switch. The slack on thecord I9 will be suflicient to ensure that downward movement of thehandle or grip member and the corresponding angular movement of therocker arm to which said cord I9 is attached will not be impeded orprevented by the latter, the arrangement being such however thatfollowing actuation of the switch as above described the slack on thecord I9 will be taken up. On release of the handle or grip member thetrigger element I5 will return to the inoperative position and thepiston or plunger member I I to which the cord I8 is attached will beretained by the spring I2 in its retracted position. When the handle isagain 3 pulled downwardly again to operate the switch the cord I9 whichis attached to the casing I will be operative to move the rocker armwhile the cord 18 will be pulled upwardly due to the actuation of saidarm. Upward movement of the cord I8 i allowed by virtue of the fact thatthe piston or plunger member II can slide relatively to the casing II),the trigger element l5 not being depressed on this occasion. The axialmovement of the member I i will serve to tension the spring II thearrangement being such that upon release of the handle or grip memberthe casing I0 and the plunger member I I, will be restored to theirinitial relative positions. The spring 12 is so chosen that it will havejust suflicient tension to remain closed when the weight of the handleor grip member as a whole is supported by the cord l8 which is attachedto the piston or plunge member i I.

While the handle or grip member according to the invention isparticularly adapted for application to the operating cords for theswitches of hoists and similar overhead equipment, its use is notnecessarily limited thereto since it may obviously be applied in anycase where two operatingcords or the like are present which are requiredto be pulled alternately.

I claim:

1. A handle or grip member adapted to be attached to the operating cordsof a switch of the kind referred to such member comprising a firstmember to which one operating cord may be attached, a second member towhich the second cord may be attached, said two members being capable ofsliding movement relatively to each other, resilient means adapted tocouple said members together and capable of returning them automaticallyto predetermined relative positions after sliding movement, and meansoperable at will to prevent relative sliding movement of said memberswhen required.

2. A handle or grip member for attachment to the operating cords of aswitch of the kind referred to such member comprising an outer casing towhich one cord is attached, a member disposed within said casingandslidable axially relatively thereto and to which the second cord isattached, means operable to prevent sliding movement of said memberrelatively to the casing when required and means adapted to return theparts to their original positions on those occasions when relativemovement has taken place.

3. A handle or grip member as in claim 2 wherein the means forpreventing relative sliding movement comprise a depressible triggerelement mounted externally of the casing and having a portion adapted ondepression of said member to enter said casing through an aperturetherein and to engage the slidable member.

'4. A handle or grip member as in claim 3 wherein the trigger elementcomprises a leaf spring.

5. A handle or grip member as in claim 2 wherein the means for returningthe parts comprise a spring which is anchored at one end to the casingand at the other to the slidable member.

DONALD MAYER KING.

REFERENCES CITED The following references are of record in the file ofthis patent:

FOREIGN PATENTS

